The present invention relates to a fencing system, in particular, but not exclusively, to palisade fencing.
In a known type of palisade fencing, vertical pales are attached to a number of horizontal rails. These in turn are attached to vertical posts, which are set in the ground. The pales are usually bolted or riveted to the horizontal rails.
A pale is conventionally a strip of material such as metal of generally curved cross section, and is mounted upon the horizontal rails by its concave surface, so as to present its convex surface. When using such a palisade for an enclosed boundary, these convex surfaces are usually facing outwards. A known pale has a cross section of a flattened trefoil shape. Such a pale is usually formed by cold rolling a strip of metal.
Holes through the thickness of the pale are formed, each hole corresponding to a hole in the horizontal rail to which the pale is to be attached. A bolt is then used to fasten the pale and the horizontal rail, the head of the bolt being upon the convex surface of the pale. Similar attachment means such as rivets or the like, may be substituted.
This bolt head is very apparent, and offers an enticing target for vandals. Should the bolt head be removed, by being sheared off with a cold chisel for example, the pales may be removed and access gained to the area enclosed by the palisade. Also, while a pale with a generally curved cross section has good structural strength axially, it has poor strength perpendicular to the axis.
GB 2 241 721 (Murphy et al) discloses a method of joining the pales to the horizontal rails without using bolts, rivets or the like. The pale, having a cross section of a flattened trefoil shape, also features a lip along each vertical edge. A clamping plate engages with these lips, and this is then bolted or riveted to the horizontal rail. In this manner the fastening means is concealed from someone on the outside of the boundary. Similarly to a conventional pale, this pale is cold rolled.
Like a conventional pale, the pale disclosed in Murphy has poor strength perpendicular to its axis. Also the lips may deform if the pale is pulled upon, so allowing the pale to be detached from the horizontal rails.
The object of the present invention is to provide a system of fencing which is both structurally strong, and conceals its means of attaching the component parts when regarded from one side of the fencing.
According to the present invention, there is provided a fencing system including a plurality of substantially vertical pales, one or more substantially horizontal rails, the rails including a substantially flat surface against which the pales are set, and holes through which a bolt or the like may pass to secure the pales.
Preferably the section of the pale is elongated parallel to the rail, and preferably includes a generally convex surface facing away from the rail, and a generally concave or re-entrant surface, the fastening means engaging with this surface and being concealed by this surface when the pale is regarded from side of the pale opposite to the concave surface.
Preferably the concave surface of the pale and surface of the rail (or an intermediate member situated between the rail and the pale) which it faces are, at least before fastening, of different shapes so that a portion of the concave surface is not directly in contact with the rail, and the fastening means pull upon this portion of the concave surface of the pale such that it becomes prestressed.
Preferably the securement means include a bolt passing through both the rail and the concave surface. Preferably the generally concave surface includes a flat central portion. The pale is preferably formed by extrusion.
According to another aspect of the present invention, there is provided a pale as herein defined, and a method of erecting a fencing system comprising supporting a rail horizontally in its intended final position, and fastening a plurality of such pales.
The pale, when viewed in cross section, has a rear wall comprising a curved surface which is arranged against the horizontal rails and attached thereto, this rear wall forming part of the hollow section. When the fence is approached from the front, the concavity of the rear wall will shield the securement means.
Furthermore, a securement means, such as a bolt, common to both the rail and the pale and which tends to pull the curved surface of the pale towards the rail, will tend to flatten the concavity and prestress the pale, making the pale more rigid against the rail and making it very difficult to gain access to the securement means through the regions where the rail and pale abut.